The present invention pertains to a process of making gona-1,3,5 -(10),9(11)-tetraenes such as those having the following formula ##STR2## in which formula N IS 1 OR 2,
R.sup.1 is a hydrogen, hydroxy, alkoxy, pyranyloxy, or alkanoyl substituent, PA1 R.sup.2 is a hydrogen, alkoxy, acetoxy, alkyl, alkenyl, or alkynyl substituent, or a substituent having the formula --CH.sub.2 X in which X is a halogen, pseudohalogen, or O-alkyl substituent, or PA1 R.sup.1 and R.sup.2 together are oxygen, or a methyleneoxy or ethylenedioxy substituent, PA1 R.sup.3 is a hydroxy, alkoxy, alkanoyl, or alkoxymethyleneoxy substituent, and PA1 R.sup.4 is a methyl or ethyl substituent. PA1 R.sup.1 is a hydrogen, hydroxy, alkoxy, pyranyloxy, or alkanoyl substituent, PA1 R.sup.2 is a hydrogen, alkoxy, acetoxy, alkyl, alkenyl, or alkynyl substituent, or a subsituent having the formula --CH.sub.2 X in which X is a halogen, pseudohalogen, or O-alkyl substituent, or PA1 R.sup.1 and R.sup.2 together are oxygen, or a methyleneoxy or ethylenedioxy substituent, PA1 R.sup.3 is a hydroxy, alkoxy, alkanoyl or alkoxymethyleneoxy substituent, and PA1 R.sup.4 is a methyl or ethyl substituent.
The preparation of 3-hydroxy-13.beta.-methylgona- 1,3,5(10), 9(11)-tetraen-17-one and 3-methoxy-13.beta.-methylgona-1,3,5(10),9(11)-tetraen-17-one by reactions of 3-hydroxy-13.beta.-methylgona-1,3,5(10)-triene and 3 methoxy-13.beta.-methylgona-1,3,5(10)-triene, respectively, with 2,3-dichloro- 5,6-dicyanobenzoquinone has been described by W. Brown, J. W. A. Findlay, and A. B. Turner in Chemical Communications, 1968, pages 10-11, and with adamantanol by W. H. Lunn and E. Farkas in Tetrahedron, vol. 24, pages 6773-6776 (1968).
The preparation of 3-hydroxy-13.beta.-methylgona-1,3,5(10),9(11)-tetraen-17 -one and 3-alkyl ethers thereof by reaction of 3-hydroxy-13.beta.-methylgona-1,3,5(10)-trien-17-one with antimony pentafluoride and fluosulfonic acid was described by J. P. Gesson, J. C. Jacquesy and R. Jacquesy in Tetrahedron Letters No. 49, pages 4733-4736 (1971).
Although yields between 60 and 70% of the theoretical can be obtained in accordance with the foregoing processes, they have the disadvantage that expensive reagents or reagents that are not suitable for commercial use are required. Another disadvantage of these processes for the production of gona-1,3,5(10),9(11)-tetraenes from 3-hydroxy-13.beta.-methylgona-1,3,5(10)-trienes are the reactions with chlorine, bromine, or iodine that are required to produce these compounds, either in a 2-step process from 10.beta.-chloro-13.beta.-methylgona-1,4-dien-3-one or in a synthesis involving the production of 3,3-(1-oxo-2-methylpropylene-1,2-dioxy)-10.beta.-bromo-13.beta.-methylgona -1,4-diene or the corresponding iodo compound. Higher yields can be obtained only by large expenditures for syntheses, whereas lower yields are obtained with the less-used processes.
It is also known that 3-methoxy-13.beta.-methylgona-1,3,5(10),8(9)-tetraene that can be obtained by total synthesis can be partially converted to 3-methoxy-13.beta.-methylgona-1,3,5(10),9(11)-tetraene. Since this rearrangement is not complete, and both isomers are difficult to separate from each other, this process is of little importance.
A further possibility of introducing a 9(11) double bond in gona-1,3,5(10)-trienes consist in dehydrating an 11-hydroxy-13.beta.-methylgona-1,3,5(10)-triene. Since 11-hydroxy-13.beta.-methylgona-1,3,5(10)-trienes however are not readily accessible, this process also is of little importance for the preparation of 13.beta.-methylgona-1,3,5(10),9(11)-tetraenes from readily producible 13.beta.-methylgona- 1,3,5(10)-trienes.